The widening ability to associate people's real-life identities with their browsing habits marks a privacy milestone. In pursuit of ever more information, tracking companies are redefining what it means to be anonymous.

Many popular Facebook apps obtain sensitive information about users—and users' friends—so don't be surprised if details about your religious, political and even sexual preferences flow to unexpected places.

Lenovo's chief technology officer, Peter Hortensius, acknowledged that "we didn't do enough" due diligence before installing Superfish, but that the company doesn't believe laptop owners were harmed by the app.

Google is opposing a proposal that would make it easier for law enforcement to get warrants to hack into computers, the latest skirmish between Silicon Valley and the U.S. government in the wake of Edward Snowden's revelations about widespread spying.

The Dutch government is reluctant to scrap the law for security reasons. Authorities are seeking to broaden surveillance powers following recent terrorist attacks in Paris and Copenhagen and a growing number of homegrown radical Muslims.

Watched: A Wall Street Journal Privacy Report

As surveillance technologies decline in cost and grow in sophistication, tracking of many aspects of our daily activities, even the seemingly mundane, has become the default rather than the exception. The Wall Street Journal's Watched project—the latest in a years-long series on privacy—explores the impact of ubiquitous surveillance on citizens and society.

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A Wall Street Journal study suggests office-supply site Staples.com offers different prices to people after using their computer's "IP address" to estimate their ZIP Code. See what the Journal found in your area.

The Wall Street Journal tested popular websites to see what personal and identifying information they shared with other companies when people log in or register. See which sites shared what information.

The Journal's Research Methodology

The Journal conducted a series of tests on a variety of commercial websites to find out which Internet retailers show different prices and products to different consumers. Here's an overview of the process.

The Wall Street Journal tested 50 of the most popular sites in the U.S. – plus WSJ.com and 20 additional websites in sensitive categories – to identify data about their registered users they passed to other companies. Here's how those tests worked.

If you've shopped for a car online on Cars.com or other automotive websites recently, there's a good chance Dataium LLC was watching most of your mouse-clicks. Here's how the Journal tested Dataium's code and what it found.

The Wall Street Journal analyzed 100 of the most-used applications that connect to Facebook's social-networking platform to see what data they sought from people's profiles. Here's how the study was conducted.

The WSJ Data Transparency Weekend

The Wall Street Journal's first-ever Data Transparency Weekend brought more than 100 computer programmers together to develop tools that help people learn about how their data is shared online--and what they can do about it.
Winners include a service that lets you see all the information--from location to address book info--that your phone is transmitting, as well as a simple website that aims to let people to have private, encrypted chats without downloading complicated software.